Manufacture of soap-thickened compositions and apparatus therefor



1949. c R. HETHERINGTON 2,461,276

MANUFACTURE OF S OAP- THICKENED COMPOS ITIONS AND APPARATUS THEREFOR Filed Nov. 12, 1946 2 Sheets-Sheet 1 INVENTOR'HI Charles R.He1her ing1on .FIG.I I

1 ATTORNEYS 1949- c. R. HETHERINGTON 7 MANUFACTURE OF SOAP-THICKENED COMPOSITIONS v AND APPARATUS THEREFOR Filed Nov.-12, 1946 2 Sheets-Sheet 2 FI-G.]I

LEGEND Soap I Heavy Greaee Y Charles R. Heiheringron' Flnlshed Grease O ATTORNEYS Patented Feb. 8, 1949 UNITED STATES PATENT oFFicYE.

MANUFACTURE or soAr-rn ciiniiiiib coi rosrrrons AND APPARATUS rnsnnroa Charles Ray Hetherington, Bronxviile, N. Y., as signor to California Research Corporation, San Francisco, Calif., a corporation of Delaware Application November 12, 1946, Serial No. 709,319

6 Claims. 1

This invention relates to improvements in methods of manufacturing soap-thickened compositions, such as greases, the new products so obtained, and to apparatus for use in connection therewith.

More particularly, the invention pertains to a continuous process of manufacturing lubricating greases involving the efiicient dispersing of pre- -formed soap stock in recycled finished grease to form an intermediate component, and mutually fdispersin oil and the intermediate component to form finished product grease and finished re- :cycle grease.

Though a large percentage of processes in the petroleum industry today are continuous and largely automatic, greases continue to be manuiactured largely by batch methods. Batch methods of grease manufacture have numerous deficiencies, among which are the following: (1) ran unnecessarily large number of large kettles and blending tanks are required; (2) the amount wqof floor space per volume of product is high; (3) :quality of product is largely dependent on varyiing skill of the grease operator; (4) because product must be made in large batches, it is sub- :stantially impossible to maintain the necessary :uniform conditions of temperature and mixture throughout the batch, with the result that it is difiicult to obtain uniformity of product; (5) be- :cause of inherent poor mixing when handling large batches of material, maximum utilization of the soap stock is not obtained, with the result that more soap stock is required to produce a given penetration grease and more of the expensive soap stock is required.

One object of the present invention is to overcome the disadvantages of the batch methods. According to the hereindescribed invention, the costs of production are decreased, the grease is not only improved in quality but is uniform. The amount of equipment employed is greatly reduced and the quality of the grease rendered substantially independent of the skill of the operator. In addition, a further saving is obtained because my process permits a reduction in the amount of soap required, soap being the most expensive ingredient of the grease. Furthermore, according to the present invention, light greases containing a comparatively low percentage of soap may be efiiciently made in a continuous manner.

My invention may be understood from the following description which has reference to Figure I wherein my invention is diagrammatically illustrated. Preformed soap stock continuously metered from soap stock kettles A and B by variable machine 20 is finished grease.

2 drive metering pump I0 flows through line I2. Mineral oil is continuously drawn into the system from mineral oil storage tanks 0 and D by variable drive metering pump I3 through meter I4.

The soap stock passes from line I2 through heater I5 for temperature control to the first stage mixing machine I6 wherein it is violently mixed with recycled finished grease supplied by pump II through line I8. The material effluent through line I9 from first stage mixer I6 is the intermediate component. It is a dispersion of soap stock and finished grease, the finished grease containing in itself, even prior to admixture with the soap stock, the amount of soap desired in the finished product The intermediate component effluent from the first stage mixing machine I6 flows continuously through line I9'to the second stage mixing machine 20 wherein it is continuously admixed with proportioned quantities of heated mineral oil stock supplied at controlled temperatures by metering pump I3 through line 2I and heater 22. Material continuously efiiuent through line 23 from the second stage mixing This finished grease flows continuously through line 23, through recycle pump I! to a junction 24 where finished, recycle grease splits continuously to line I8, and finished, product grease flows continuously through line 26 through a strainer 2'! and back pressure controller 28 to product storage 29. The proportion of the finished grease which is to be recycled to the first stage mixing machine I6 through line 18 may be controlled by by-passing finished grease around recycle pump I'I through a by-pass 30 and valve 3 I. I

First stage mixing machine I6 and second stage mixing machine 20 may be any of the numerous high speed mixing machines or dispersers available on the market for dispersing or mixing of this character. One type commonly used is known as the Lancaster disperser. Centrifugal pumps, colloid mills, disc mills, screw pumps and similar equipment, capable of providing intimate mixture and fine dispersion of heavy materials, may be employed as the mixing devices. Usually such equipment obtains its dispersing action by the shearing action of rapiding moving parts and by the use of directing'vanes and baffies. A common feature of all such devices, as applied to my process, is their ability to effect an intimate dispersion of the soap stock and recycled'finished grease at one stage and the intermediate com: ponent and the mineral oil in another stage a very short period of time, usually about to seconds.

The above description of my invention is illustrative only and covers only one embodiment of the invention of the appended claims. Ob-

' viously the number of stages employed and the the grease structure continuously circulated back to the first stage disperser may be any intermediate grease structure continuously formed in said continuous process. 7

It will be noted that the hereindescribed process may be operated on a fully continuous andautomatic basis. Havingonce made ap propriatecontrol .settingsfor, temperature and rate. of how ,of the incoming soap stock and mineral oil stock, .the rate of recycling of the finished grease, and having made appropriate settings on metering pumps It! and J3, heaters 15 and 22 and finished grease by-pass valve 3i, the process is continuous and fully automatic. As such,,it is independent of the varying skill of the particular operator and the finished grease is uniform in nature. Obviously apparatus for thepraotice of my process may be equipped with appropriate control mechanisms, valves and the like, so that theprocess can be operated on a nonautomaticbasis, if desired. a I,.cl o not, of course, claim to be the firstto have disclosed a continuous process of vmanufacturihg soap-thickened compositions. Among the United States patentsdescribing, continuous grease-making processes. are Nos. 1,912,001; 2, 084,974.; 2,318,668; 2,332,202; 2,365,037; 2,374,913; 2,383,906; 2,394,561,, My proces'sarid apparatus, however, are novel. andfpossess outstanding ,ejdvantages over the processes 'and apparatus disclosed in'the'prior art H .One pi'ocess for continuous manufacture of greases provides for continuously passingproportibhed and heated amounts of soap stocka'n'd soaparree n stock to a high speed mixer wherein the grease structureiis formed by means of the shearing action of rapidly moving parts, as in the device known in the industry as a Lancaster disperser. One disadvantage of such process is especially pronounced in the mainlfacture of light greases, i. e., greases containing 10% or less of soap. In such manufacturepo'ntrol for product consistency has been difficult to obtain, in part because there is not obtainedan efiec'tivemutua'l dispersion of the soap andpil. Suchincomplete dispersion of the soap and the mineral oil results in 'a finished grease which'is unstable and which tends to bleed upon standing. The incomplete dispersion of the soap'stock in the oil and the consequent tendency of the finished grease to bleed Where the dispersionis accomplished by high speed mixing of soap stock and oil is believed tobe caused, especially when the percentage of. soap stock is comparatively low, bythe wide disparity between the physical properties of the soap stockand of the oil. In my. process, in the soap, dispersing step, the materials are of substantiallymore similar physical properties and themutual dispersion .of the soap and the, other components is intimate and complete.

4 In Figure I, I have shown a purely diagram matic exemplification of my process. Reference is now made to Figure II wherein I have shown a longitudinal sectional View of a preferred apparatus for carrying out the mixing and circulating phases of my process. The apparatus of Figure II per 'se is described and claimed in a copending joint application in the name of the herein inventor and Eldred E. Edwards, which application was filed November 12, 1946, and bears Serial No. 709,290. In Figure 11, reference numeral 43 designates generall a plate or other suitable type of end member,- provided with acentral shaft aperture and fstufiing box M. An opposite end member 42 is spaced from member 4! by means of a cylindrical housing or shell 43, the whole assembly being fastened together with through bolts 4d, equally spaced around the peripher of shell 53. A shaft 41 adapted to be driven by a prime mover (not shown) extends through stuflingbox Hand is received in a central bearing 18 in end member 52 Bearing 4t isprovided with a plurality of openings 19 adaptedto communicate with a central port 59 in housing 42 for the purpose of admitting soap stools, represented by dotted arrows, substantially uniformly around that end of shaft which is received in bearing 48 Mounted on shaft 41in this egample, are three impellers, respectively designated 5!, 52 and 53, of the type generally usedincentrifugal pumps. These are spaced along shaft 41' by sleeves 5d and 55 and are secured to; the shaft by the customary keys (not shown and'a threaded nut 56, adjacent the outboard Or-bearing endofshaft 4'l. a i v Wi thin the housing shell 43 are provided dif fusion vane assemblies 51, 58 and 59 similar to those utilized in turbine type centrifugal pumps. Two inlets '68 and 6! are provided in the end member 58 to communicate with an iulet eye of mixing impeller 5i. I facilitate th is communication, a first diaphragm 52 having a central aperture is positioned within the housing shell di een t b sp c om t i n r i s e of end member 58 and the inlet eye piximpeller 5!, A second diaphragm 53 is positioned on the opposite side of mixing impeller '55 from diaphragm 6 2 and is provided with apertures 54 nearitsperiphery so that a portion of the fluids or semi-fluids passing outwardly from impeller 5i into diflusion vanes 51' will be redirected inwardly toward shaft GI to-passthrougha oeui el p tel in, t d phra it .ir m which the fluids or semi-fluids willbe admitted to. t et eye of a Pu p n .imP ls t-.: which is the center impeller of the three in this pl Desirably aportion of the fluidspii semi-fluids passing through impeller 5i intodifiusion vanes 51 r u a s a h w by t e arrow .t reen the inlets of that impeller and insure maximum turbulence a misie A fourth diaphragm 5! i s-'posit ioned"on the oppositeside of pumping impeller EZiIQm diaphragm stand, similar to diaphragm 63, is provided around its periphery with apertures 68 to cooperate with a fifth diaphragm 59 toredirect at least a portion of the fluids, or semi-fluids passing outwardly from impeller 52, through" the space between diaphragms 5i and 6}! to a central aperture 18 in the latter diaphragm which'acts finally to direct the fluids or semi-fluids? intoian'inl'et or eyemof the third or mixingv impelieri"53 "The clearance or'spacing between diaphragmstfirand 61 and impeller 52 is as close as practicable, so that eificient pumping action will be obtained from this impeller.

As pointed out above, fluids or semi-fluids, in

this example soap stock represented by dotted arrows, admitted through port 50 enter the opposite eye of mixing impeller 53 from that just described so that mixing of the respective fluids or semi-fluids will take place within the lastnamed impeller and its corresponding difiuser 59. It will be noted from the arrows on the drawing that recirculation from the periphery of impeller 53 inwardly to the eyes thereof is facilitated by the spacing between diaphragm 69 and the adjacent face of the impeller. Two outlets are provided from the cylindrical shell 53, the first, designated by numeral 1 1, communicating with difiusion vanes 58 for pumping impeller 52, and the second, designated by numeral l2, communicating with difiusion vanes 59 for mixing impeller 53. Desirably, outlet 12 is provided witha conduit is in which is mounted valve means M, so that the intermediate component represented by dashed arrows, passing outwar iy from the space surrounding mixing impeller 53 may be controllably recirculated to inlet 0!, whereby this material will be introduced and dispersed with the mineral oil (second component), represented by the dash-dot arrows, entering inlet 60 to pass to the inlet eye of mixing impeller 51.

In operation, the apparatus of Figure II just described may take the place of mixers l6 and as well as recycle pump i1 and bypass of Figure I. With such an arrangement, mineral oil, represented by dash-dot arrows, is admitted through inlet 60, soap stock, represented by dotted arrows, is admitted through inlet 50, and finished grease, shown by solid line arrows, is dischargedfrom outlet 1 l. Recirculation of finished grease into the soap stock to provide the intermediate component, as described above, takes place through valved conduit 13.

Though the process and apparatus of my invention have special utility in the manufacture of lime base greases, it is also adapted for use in connection with production of other commonly used greases, such as aluminum base grease and sodium base grease. In the manufacture of aluminum base greases the finished product grease as described in Figures I and II is preferably cooled quickly to about 120-180 F. and then allowed to stand, undisturbed, at a constant temperature for about 15 minutes to 24 hours until the desired aluminum base grease structure has formed.

The soap stock used in my process and apparatus may be made by any of the numerous methods well known in the art. Any of the various fats, fatty oils, fatty acids and the like ordinarily used as saponifiable materials in grease making may be employed, including oleic acid, stearic acid, hog fat, tallow, fish oils, saponifiable vegetabEe and animal oils, naphthenic acids, etc. Depending upon the type of grease desired and its use, any of the well known saponifying agents may be used, including calcium hydroxide, calcium oxide, magnesium, barium, strontium and lithium hydroxides or oxides, caustic soda, caustic potash, aluminum hydroxide, etc. Instead ofpreparin the soap, commercially manufactured dry soaps suitable for grease manufacture may be employed. When such procedure is followed, I usually insert the anhydrous soap in appropriate medium or carrier, such as a naphthenic base mineral oil of about 300 S. S. U. viscosity at 100 the type of grease to be made.

be maintained at proper temperatures.

6 F., or the like, and subject it to thorough mixing prior to dispersion in the recycled portion ofthe finished grease.

Naturally the type of soap stock employed will vary, according to well-known principles, with the kind of grease to be made and with the components of the grease.

Though it is not necessary that it be done, a small portion of the oil stock may be admixed with the soap before the soap stock is pumped into the system.

In the manufacture of lime base soap stocks it is usually desirable, and even necessary with most processes, to provide for the presence in the grease of a small percentage of water. The water content of lime base soap stocks varies in the range of 5-20% of the dry weight of the soap present. Such water is usually incorporated in the saponification step in the soap manufacture.

Of course, in operating my process as a fully continuous process, it is necessary to have a continuous supply of soap stock. Accordingly, an adequate number of soap kettles may be employed to supply the demand of the process for the soap stock. The charges to the soap kettles should be so timed that when the contents of one soap kettle has been used the soap from another kettle is available. Likewise, a continuous supply of oil must be available if the process is to be operated continuously.

The mineral oil stocks used may be those conventionally employed in grease manufacture, including mineral lubricating oils obtained from paraffinic, naphthenic and mixed base crudes,

( with or without various treatments usually given such oils. Oils obtained by polymerization, condensation, hydrogenation, etc, of hydrocarbons may also be used. lhe preferred viscosity of the mineral oil stock will usually vary according to For aluminum soap grease, sodium soap grease and calcium soap grease preferred viscosity ranges, expressed in Saybolt seconds Universal at 210 F'., are respectively, -300, 40-300 and 40-200.

In my process, where the dispersion is obtained largely with the aid of the high speed mechanical disperser, it is nevertheless important that in the various mixing steps the soap stock, oil, intermediate component and recycled finished grease In the table are shown preferred temperatures at various stages of my process in the manufacture of lime, aluminum and sodium base greases.

The proportions of soap stock and oil stock which will exist in the grease when it leaves the system will vary, of course, with the type of grease being made and its intended purpose. Soap content of greases varies from as low as 1% to as high as and higher. The determination of what percentages of soap and oil stock to use to obtain the desired grease is one easily made by those normally skilled in the grease-making art. While our process and apparatus has special energet c 7 utilityin the manufacture of grease'with-a soap content of 10%. or less, my invention is not limited to any specific range of soap percentages.

It is usually desirable to maintain the various elements, including soap stock vessels and oil supply vessels, pumps, mixers, etc. under superatmospheric pressure of around 25 pounds per square inch. This is especially true in the manufacture of lime base greases, inasmuch as such greases normally contain considerable Water which should not be lost by evaporation.

I claim:

Continuous process of making grease, which comprises continuously intimately admixing proportional amounts of preformed soap stock and preformed grease to form an intermediate uniform dispersion, and continuously intimately admixing said uniform dispersion with a proportional amount of oil to form another uniform dispersion characterized by high stability and a reduced soap content as compared with the first mentioned dispersion.

2. Ina continuous process of making grease wherein proportioned amounts of preformed soap stock and oil are subjected to high speed mixing to produce a dispersion of oil and soap stock, the improvement which comprises subjecting said soap stock in the presence of a proportioned amount of preformed grease to the action of a high speed mixer prior to forming a dispersion of said soap stock and oil, whereby said soap stool: is conditioned for more eficient andstable dispersion in the oil.

3. in a continuous process of making grease of improved stability wherein proportioned amounts of preformed soap stock and oil are subjected to the action of a high speed mixer to produce a dispersion of soap stock and oil, the im rovement which comprises subjecting said soap stock to the dispersing action of a high speed mixer in'the presence of a proportioned amount 01 preformed grease prior to subjecting said soap stock to a further dispersing actionin the presence of oil, said preformed grease being continuously recirculated grease resulting from the last mentioned dispersing action.

4. In a continuous process of making grease wherein proportioned amounts of preformed soap stock and oil are subjected to the action of a high speed-mixer to produce a dispersion of soap stock and oil, the improvement which comprises sub- S jeoting' preformed soap stock dispersed in preformed grease and -a proportioned amount of oil to the dispersing action of a high speed'mixer to produce a" dispersion of oil and soap stock of improved stability.

Continuous process of making grease which comprises continuously passing to a high-speed disperser proportioned amounts of preformed soap stock and proportioned amounts of preformed grease, effecting an intimate dispersion of said soap stock and preformed greasein such first stage disperserto form an intermediatecomponent, continuously passing such intermediate component and proportioned amounts of oil to a second high-speed disperser, efiecting an intimate dispersion or" said two components in said second disperser and recirculating proportioned amounts or the product of such second disperser tothe first stage disperser as the finished grease component of the first stage disperser.

6. Continuous multistage process of grease making which comprises continuously passing proportioned amounts of preformed soap stock (component i) and proportioned amounts of preformed grease continuously recirculated from a later stage invsaid multistageprocess (component it) p to a high speed disperser, continuously effectintimate dispersion of components 1 and 2 'in said disperser by the shearingaction of rapidly moving'parts, continuously passing proportioned amounts. of said dispersion (component 3) and oil (component 4) tea second such highspeed disperser, and continuously eiiecting an intimate dispersion in said second disperser. oi-

proportioned amounts of components 3 and4. CHARLES RAY HEIHERINGTON.

REFERENCES CITED The'following references are of record in the file of th'ispatent:

UNITED STATES PATENTS Houlton lMaI'. 18, 1947 

